5 This was totally spontaneous, entirely their own idea, and caught us completely off guard. What explains it was that they had first given themselves unreservedly to God and to us. The other giving simply flowed out of the purposes of God working in their lives.
Matthew Henry's Commentary on 2 Corinthians 8:5
Commentary on 2 Corinthians 8:1-6
(Read 2 Corinthians 8:1-6)
The grace of God must be owned as the root and fountain of all the good in us, or done by us, at any time. It is great grace and favour from God, if we are made useful to others, and forward to any good work. He commends the charity of the Macedonians. So far from needing that Paul should urge them, they prayed him to receive the gift. Whatever we use or lay out for God, it is only giving him what is his own. All we give for charitable uses, will not be accepted of God, nor turn to our advantage, unless we first give ourselves to the Lord. By ascribing all really good works to the grace of God, we not only give the glory to him whose due it is, but also show men where their strength is. Abundant spiritual joy enlarges men's hearts in the work and labour of love. How different this from the conduct of those who will not join in any good work, unless urged into it!